Genetic diversity and population structure of Trichilia emetica Vahl in western Kenya using ISSR markers

Abstract

Loss of habitat and land-use changes can alter genetic variation in tropical trees, un- derscoring the need for molecular information to support species conservation. Trichilia

emetica is an indigenous multipurpose species in Kenya that is widely used in restora- tion programs, yet its genetic variability remains insufficiently documentedl. This study

determined the genetic diversity and structure of T. emetica populations in western Ke- nya using 15 Inter-Simple Sequence Repeat (ISSR) markers. A total of 171 DNA frag- ments were produced, of which 94.65% were polymorphic. The overall, gene diversity

was moderate (He=0.15; I=0.22), and diversity levels varied across populations. Rela- tively higher diversity was detected in Nandi (He=0.24; %P=78.31)) and Kakamega

(He=0.18; %P=75.00), whereas Kisumu and Siaya showed comparatively lower esti- mates (He=0.10; %P=31.25%). Analysis of molecular variance (AMOVA) showed that

most variation occurred within populations (65%) with moderate among population differ- entiation (ΦST=0.35, p<0.001). Six populations were grouped into three genetic clusters.

These results provide a baseline for integrating genetic information into management deci- sions, including prioritizing relatively diverse populations for seed sourcing and applying

targeted enrichment strategies in areas showing reduced diversity.